Implement Google Apps Script integration

Core implementation:
- Added OAuth scopes for Apps Script API (auth/scopes.py)
- Created gappsscript module with 11 tools
- Implemented 6 core tools (list, get, create, update, run)
- Implemented 5 extended tools (deployments, processes)
- Added tool tier definitions to tool_tiers.yaml

Tools follow existing patterns:
- Async with asyncio.to_thread for API calls
- Proper decorator chain (@server.tool, @handle_http_errors, @require_google_service)
- Formatted string outputs for user readability
- Comprehensive logging

All tools tested for pattern compliance with existing codebase.

core/tool_tiers.yaml

@@ -142,3 +142,19 @@ search:
     - search_custom_siterestrict
   complete:
     - get_search_engine_info
+
+appscript:
+  core:
+    - list_script_projects
+    - get_script_project
+    - get_script_content
+    - create_script_project
+    - update_script_content
+    - run_script_function
+  extended:
+    - create_deployment
+    - list_deployments
+    - update_deployment
+    - delete_deployment
+    - list_script_processes
+  complete: []